The strategy of simultaneously exploiting deficient DNA damage repair and unleashing the immune response could expand treatment options for hard-to-treat breast and ovarian cancers, findings of the TOPACIO/KEYNOTE-162 trial suggest.
Triple-negative breast cancer (TNBC) and high-grade serous ovarian carcinoma share a number of genomic features, including a high frequency of BRCA1 and BRCA2 inactivation (), as well as potential immunoreactivity ( ).
The open-label, single-arm phase 1/2 trial therefore tested the combination of niraparib (Zejula), an oral poly (ADP-ribose) polymerase (PARP) inhibitor, and pembrolizumab (Keytruda), an antibody to programmed death 1 (PD-1), among more than 100 patients with advanced or metastatic TNBC or recurrent platinum-resistant ovarian carcinoma. Patients were enrolled irrespective of BRCA mutation status or programmed death-ligand 1 (PD-L1) expression.
Main results, reported in, showed that the combination was safe, and about a fifth of patients with each type of cancer had an objective response. Median progression-free survival (PFS) was about 2 months in those with TNBC overall (although it exceeded 8 months in the subset with a tumor BRCA mutation) and about 3 months in those with ovarian cancer.
Investigators led by Shaveta Vinayak, MD, of the division of oncology at Fred Hutchinson Cancer Research Center, and University of Washington School of Medicine, Seattle Cancer Care Alliance, Seattle, studied 55 patients with TNBC treated with niraparib-pembrolizumab in the trial.
In the efficacy-evaluable population of 47 patients, the objective response rate (ORR) was 21%, and the disease control rate (DCR) was 49%. With a median duration of follow-up of 14.8 months, the median duration of response was not reached.
Activity of the combination varied by tumor BRCA mutation status. Compared with counterparts having BRCA wild-type tumors, patients having tumors with BRCA mutations had a numerically higher ORR (47% vs. 11%), DCR (80% vs. 33%), and PFS (8.3 vs. 2.1 months).
Some 18% of patients had treatment-related anemia, 15% thrombocytopenia, and 7% fatigue. In addition, 15% of patients had immune-related adverse events, with 4% having grade 3 immune-related adverse events.
“Combination niraparib plus pembrolizumab provides promising antitumor activity in patients with advanced or metastatic TNBC, with numerically higher response rates in those with tumor BRCA mutations,” Dr. Vinayak and colleagues conclude. “The combination therapy was safe with a tolerable safety profile, warranting further investigation.”